586] SELECTION OF A CHARACTER 



be formed by selection and propagated three dis- 

 tinct strains of winter egg producers, namely, high, 

 mediocre and low. This involved, on the individ- 

 ual performance side, the separate selection in the 

 first years of three classes of females as breeders : 

 (a) good winter producers, with records before 

 March 1 of above 30 eggs; {b) mediocre winter 

 producers, with records below 30 eggs; and (c) 

 poor winter producers, which laid no eggs before 

 March 1. The division at 30 eggs was, after the 

 first year, merely a nominal one in the selection of 

 high producers. Actually only birds were used 

 in the a class whose records materially exceeded 

 30 eggs, running up to over 100 eggs in some 

 cases. 



The progeny performance idea was carried out in 

 two ways in the breeding. In the first place, no 

 female was selected for the high winter produc- 

 tion breeding pens, for example, unless, in addi- 

 tion to her own high winter record, all her sisters 

 and her dam wore high producers. In the second 

 place, of all females fulfilling the above qualifica- 

 tion only those were bred a second time whose 

 progeny from the first year's mating had proven 

 to be all high producers. Similar types of selec- 

 tion were followed by the mediocre and low lines, 

 except that segregating families were put in the 

 mediocre class. 



The selection of males was along essentially the 

 same lines, with only such difference as is in- 

 volved in the fact that the male makes no per- 

 formance record himself. Males were put into 

 the breeding pen the first time on the basis of the 

 records of their dams, on the one hand, and of 

 their sisters, on the other hand. Those whose 

 progeny proved that they were transmitting the 

 character to which selection was being made were 

 used a second or even third time as breeders. 



Complete individual pedigrees, whereby each off- 



